Querying typed hypertexts in Multicard/O2

Due to the growing complexity of modern hypertext applications, current hypertext systems require new mechanisms to support authoring and user navigation through large sets of documents connected by links. A general solution is to extent hypertext systems to cater for semantics of application domains. This requires new hypertext models providing strongly typed documents and links. Such models have been proposed and put to use in systems such as HDM and MacWeb to facilitate authoring of large hypertexts. In addition, Gram and MORE use typing and graph-based hypertext schemas for querying hyperdocuments. In this paper, we will show how query languages could be further exploited for designing sophisticated general query-based navigation mechanisms. We illustrate our examples using the Gram model and describe an implementation with the hypermedia system Multicard connected to the object-oriented database management system O2.